feat: Add real DrugBank DDI dataset support via TDC

- Added PyTDC dependency for DrugBank access
- Implemented DDI type -> severity label mapping (0-4)
- Added train/eval split with stratification
- Added accuracy and F1 metrics for evaluation
- Default: 50K samples from DrugBank DDI
- Supports both real data and custom inline data

components/runpod_trainer/handler.py

@@ -2,7 +2,7 @@
 RunPod Serverless Handler for DDI Model Training
 
 This runs on RunPod GPU instances and trains the Bio_ClinicalBERT model
-for drug-drug interaction detection.
+for drug-drug interaction detection using real DrugBank data via TDC.
 """
 import os
 import json
@@ -10,6 +10,119 @@ import runpod
 from typing import Dict, Any, List, Optional
 
 
+# DrugBank DDI type mapping to severity categories
+# TDC DrugBank has 86 interaction types - we map to 5 severity levels
+DDI_SEVERITY_MAP = {
+    # 0 = No significant interaction / safe
+    'no known interaction': 0,
+    
+    # 1 = Minor interaction (mechanism-based, low clinical impact)
+    'the metabolism of drug1 can be increased': 1,
+    'the metabolism of drug1 can be decreased': 1,
+    'the absorption of drug1 can be affected': 1,
+    'the bioavailability of drug1 can be affected': 1,
+    'drug1 may affect the excretion rate': 1,
+    
+    # 2 = Moderate interaction (effect-based, monitor patient)
+    'the serum concentration of drug1 can be increased': 2,
+    'the serum concentration of drug1 can be decreased': 2,
+    'the therapeutic efficacy of drug1 can be decreased': 2,
+    'the therapeutic efficacy of drug1 can be increased': 2,
+    'the protein binding of drug1 can be affected': 2,
+    
+    # 3 = Major interaction (significant risk, avoid if possible)
+    'the risk or severity of adverse effects can be increased': 3,
+    'the risk of bleeding can be increased': 3,
+    'the risk of hypotension can be increased': 3,
+    'the risk of hypertension can be increased': 3,
+    'the risk of hypoglycemia can be increased': 3,
+    'the risk of hyperglycemia can be increased': 3,
+    'the risk of QTc prolongation can be increased': 3,
+    'the risk of cardiotoxicity can be increased': 3,
+    'the risk of nephrotoxicity can be increased': 3,
+    'the risk of hepatotoxicity can be increased': 3,
+    
+    # 4 = Contraindicated (avoid combination)
+    'the risk of serotonin syndrome can be increased': 4,
+    'the risk of rhabdomyolysis can be increased': 4,
+    'the risk of severe hypotension can be increased': 4,
+    'the risk of life-threatening arrhythmias can be increased': 4,
+}
+
+
+def get_severity_label(ddi_type: str) -> int:
+    """Map DDI type string to severity label (0-4)."""
+    ddi_lower = ddi_type.lower()
+    
+    # Check exact matches first
+    for pattern, label in DDI_SEVERITY_MAP.items():
+        if pattern in ddi_lower:
+            return label
+    
+    # Default heuristics based on keywords
+    if any(x in ddi_lower for x in ['contraindicated', 'life-threatening', 'fatal', 'death']):
+        return 4
+    elif any(x in ddi_lower for x in ['severe', 'serious', 'major', 'toxic']):
+        return 3
+    elif any(x in ddi_lower for x in ['increased', 'decreased', 'risk', 'adverse']):
+        return 2
+    elif any(x in ddi_lower for x in ['may', 'can', 'affect', 'metabolism']):
+        return 1
+    else:
+        return 0  # Unknown/no interaction
+
+
+def load_drugbank_ddi(max_samples: int = 50000) -> List[Dict[str, Any]]:
+    """
+    Load DrugBank DDI dataset from TDC (Therapeutics Data Commons).
+    
+    Returns list of {"text": "drug1 drug2 interaction_description", "label": severity}
+    """
+    from tdc.multi_pred import DDI
+    import pandas as pd
+    
+    print("Loading DrugBank DDI dataset from TDC...")
+    
+    # Load the DrugBank DDI dataset
+    data = DDI(name='DrugBank')
+    df = data.get_data()
+    
+    print(f"Total DDI pairs in DrugBank: {len(df)}")
+    
+    # Sample if dataset is too large
+    if len(df) > max_samples:
+        print(f"Sampling {max_samples} examples...")
+        df = df.sample(n=max_samples, random_state=42)
+    
+    # Convert to training format
+    training_data = []
+    for _, row in df.iterrows():
+        drug1 = row['Drug1']
+        drug2 = row['Drug2']
+        ddi_type = row['Y']  # Interaction type string
+        
+        # Create text input
+        text = f"{drug1} {drug2} {ddi_type}"
+        
+        # Map to severity label
+        label = get_severity_label(ddi_type)
+        
+        training_data.append({
+            'text': text,
+            'label': label
+        })
+    
+    # Log label distribution
+    label_counts = {}
+    for item in training_data:
+        label_counts[item['label']] = label_counts.get(item['label'], 0) + 1
+    
+    print(f"Label distribution: {label_counts}")
+    print(f"Total training samples: {len(training_data)}")
+    
+    return training_data
+
+
 def train_ddi_model(job_input: Dict[str, Any]) -> Dict[str, Any]:
     """
     Train DDI detection model.
@@ -17,10 +130,13 @@ def train_ddi_model(job_input: Dict[str, Any]) -> Dict[str, Any]:
     Expected input:
     {
         "model_name": "emilyalsentzer/Bio_ClinicalBERT",
-        "training_data": [{"text": "...", "label": 0}, ...],  # Inline data
+        "use_drugbank": true,  # Use real DrugBank data
+        "max_samples": 50000,  # Max samples to use
+        "training_data": [...],  # Or provide inline data
         "epochs": 3,
         "learning_rate": 2e-5,
-        "batch_size": 16
+        "batch_size": 16,
+        "eval_split": 0.1  # Validation split ratio
     }
     """
     import torch
@@ -31,36 +147,33 @@ def train_ddi_model(job_input: Dict[str, Any]) -> Dict[str, Any]:
         Trainer
     )
     from datasets import Dataset
+    from sklearn.model_selection import train_test_split
     import tempfile
     import shutil
     
     # Extract parameters
     model_name = job_input.get('model_name', 'emilyalsentzer/Bio_ClinicalBERT')
+    use_drugbank = job_input.get('use_drugbank', True)
+    max_samples = job_input.get('max_samples', 50000)
     training_data = job_input.get('training_data', None)
     epochs = job_input.get('epochs', 3)
     learning_rate = job_input.get('learning_rate', 2e-5)
     batch_size = job_input.get('batch_size', 16)
+    eval_split = job_input.get('eval_split', 0.1)
     
-    # Use sample data if none provided
-    if not training_data:
+    # Load data
+    if use_drugbank and not training_data:
+        print("Loading real DrugBank DDI dataset...")
+        training_data = load_drugbank_ddi(max_samples=max_samples)
+    elif not training_data:
         print("No training data provided, using sample DDI dataset...")
         training_data = [
-            {"text": "warfarin and aspirin interaction causes bleeding risk", "label": 3},
-            {"text": "metformin with lisinopril is safe combination", "label": 0},
-            {"text": "fluoxetine tramadol causes serotonin syndrome", "label": 4},
-            {"text": "simvastatin amiodarone increases myopathy risk", "label": 3},
-            {"text": "omeprazole reduces clopidogrel efficacy", "label": 2},
-            {"text": "digoxin amiodarone toxicity risk elevated", "label": 3},
-            {"text": "lithium NSAIDs increases lithium levels", "label": 3},
-            {"text": "benzodiazepines opioids respiratory depression", "label": 4},
-            {"text": "metronidazole alcohol disulfiram reaction", "label": 4},
-            {"text": "ACE inhibitors potassium hyperkalemia risk", "label": 2},
-            {"text": "amlodipine atorvastatin safe combination", "label": 0},
-            {"text": "gabapentin pregabalin CNS depression additive", "label": 2},
-            {"text": "warfarin vitamin K antagonism reduced effect", "label": 2},
-            {"text": "insulin metformin hypoglycemia risk", "label": 1},
-            {"text": "aspirin ibuprofen GI bleeding increased", "label": 3},
-        ] * 10  # 150 samples
+            {"text": "warfarin aspirin the risk of bleeding can be increased", "label": 3},
+            {"text": "metformin lisinopril no known interaction", "label": 0},
+            {"text": "fluoxetine tramadol the risk of serotonin syndrome can be increased", "label": 4},
+            {"text": "simvastatin amiodarone the risk of rhabdomyolysis can be increased", "label": 4},
+            {"text": "omeprazole clopidogrel the therapeutic efficacy of drug1 can be decreased", "label": 2},
+        ] * 30  # 150 samples
     
     # Create temp directory
     work_dir = tempfile.mkdtemp()
@@ -72,27 +185,42 @@ def train_ddi_model(job_input: Dict[str, Any]) -> Dict[str, Any]:
         print(f"Epochs: {epochs}, Batch size: {batch_size}")
         print(f"GPU: {torch.cuda.get_device_name(0) if torch.cuda.is_available() else 'CPU'}")
         
-        # Load dataset
-        dataset = Dataset.from_list(training_data)
+        # Split into train/eval
+        if eval_split > 0 and len(training_data) > 100:
+            train_data, eval_data = train_test_split(
+                training_data, 
+                test_size=eval_split, 
+                random_state=42,
+                stratify=[d['label'] for d in training_data]
+            )
+            print(f"Train: {len(train_data)}, Eval: {len(eval_data)}")
+        else:
+            train_data = training_data
+            eval_data = None
+        
+        # Create datasets
+        train_dataset = Dataset.from_list(train_data)
+        eval_dataset = Dataset.from_list(eval_data) if eval_data else None
         
         # Load model and tokenizer
         print(f"Loading model: {model_name}")
         tokenizer = AutoTokenizer.from_pretrained(model_name)
         model = AutoModelForSequenceClassification.from_pretrained(
             model_name,
-            num_labels=5  # DDI severity: none, minor, moderate, major, contraindicated
+            num_labels=5  # DDI severity: none(0), minor(1), moderate(2), major(3), contraindicated(4)
         )
         
-        # Tokenize dataset
+        # Tokenize datasets
         def tokenize_function(examples):
             return tokenizer(
                 examples['text'],
                 padding='max_length',
                 truncation=True,
-                max_length=128
+                max_length=256  # Longer for drug names + interaction text
             )
         
-        tokenized_dataset = dataset.map(tokenize_function, batched=True)
+        tokenized_train = train_dataset.map(tokenize_function, batched=True)
+        tokenized_eval = eval_dataset.map(tokenize_function, batched=True) if eval_dataset else None
         
         # Training arguments
         training_args = TrainingArguments(
@@ -100,19 +228,35 @@ def train_ddi_model(job_input: Dict[str, Any]) -> Dict[str, Any]:
             num_train_epochs=epochs,
             learning_rate=learning_rate,
             per_device_train_batch_size=batch_size,
-            warmup_steps=50,
+            per_device_eval_batch_size=batch_size,
+            warmup_ratio=0.1,
             weight_decay=0.01,
-            logging_steps=10,
-            save_strategy='no',  # Don't save checkpoints (avoids tensor contiguity issues)
+            logging_steps=50,
+            eval_strategy='epoch' if tokenized_eval else 'no',
+            save_strategy='no',  # Don't save checkpoints
             fp16=torch.cuda.is_available(),
             report_to='none',
+            load_best_model_at_end=False,
         )
         
+        # Compute metrics function
+        def compute_metrics(eval_pred):
+            from sklearn.metrics import accuracy_score, f1_score
+            predictions, labels = eval_pred
+            predictions = predictions.argmax(-1)
+            return {
+                'accuracy': accuracy_score(labels, predictions),
+                'f1_macro': f1_score(labels, predictions, average='macro'),
+                'f1_weighted': f1_score(labels, predictions, average='weighted'),
+            }
+        
         # Initialize trainer
         trainer = Trainer(
             model=model,
             args=training_args,
-            train_dataset=tokenized_dataset,
+            train_dataset=tokenized_train,
+            eval_dataset=tokenized_eval,
+            compute_metrics=compute_metrics if tokenized_eval else None,
         )
         
         # Train
@@ -124,16 +268,30 @@ def train_ddi_model(job_input: Dict[str, Any]) -> Dict[str, Any]:
             'train_loss': float(train_result.training_loss),
             'epochs': epochs,
             'model_name': model_name,
-            'samples': len(training_data),
-            'gpu': torch.cuda.get_device_name(0) if torch.cuda.is_available() else 'CPU'
+            'samples': len(train_data),
+            'gpu': torch.cuda.get_device_name(0) if torch.cuda.is_available() else 'CPU',
+            'data_source': 'DrugBank' if use_drugbank else 'custom'
         }
         
+        # Run evaluation if we have eval data
+        if tokenized_eval:
+            print("Running evaluation...")
+            eval_result = trainer.evaluate()
+            metrics.update({
+                'eval_loss': float(eval_result['eval_loss']),
+                'eval_accuracy': float(eval_result['eval_accuracy']),
+                'eval_f1_macro': float(eval_result['eval_f1_macro']),
+                'eval_f1_weighted': float(eval_result['eval_f1_weighted']),
+            })
+        
         print(f"Training complete! Loss: {metrics['train_loss']:.4f}")
+        if 'eval_accuracy' in metrics:
+            print(f"Eval accuracy: {metrics['eval_accuracy']:.4f}, F1: {metrics['eval_f1_weighted']:.4f}")
         
         return {
             'status': 'success',
             'metrics': metrics,
-            'message': 'Model trained successfully'
+            'message': 'Model trained successfully on DrugBank DDI data'
         }
         
     except Exception as e:

components/runpod_trainer/requirements.txt

@@ -6,3 +6,4 @@ boto3>=1.34.0
 scikit-learn>=1.3.0
 scipy>=1.11.0
 safetensors>=0.4.0
+PyTDC>=1.1.0